package com.zoe.thread.th04_线程定制化通信;

import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

/**
 * @Author Zoe
 * @Date: 2021/05/02
 * @Description 多线程之间按顺序调用，实现A->B->C
 * 三个线程启动，要求如下：
 * <p>
 * AA打印5次，BB打印10次，CC打印15次
 * 接着
 * AA打印5次，BB打印10次，CC打印15次
 * ......来10轮
 * 1: 高内聚低耦合的前提下/线程操作资源类
 * 2: 口诀：判断/干活/通知
 * 3: 多线程交互中,必须要防止多线程的虚假唤醒，也即（判断只用while 不能用if）
 * 4: 修改标志位
 */
class ShareResource {
    private int status = 1;  // 1=A  2=B   3=C
    private Lock lock = new ReentrantLock();
    private Condition condition1 = lock.newCondition();
    private Condition condition2 = lock.newCondition();
    private Condition condition3 = lock.newCondition();

    public void printA() {
        lock.lock();
        try {
            // 1: 判断
            while (status != 1) {
                condition1.await();
            }


            // 2: 业务逻辑
            for (int i = 1; i <= 5; i++) {
                System.out.println(Thread.currentThread().getName() + "  " + i);
            }

            // 3: 通知
            status = 2;
            // 精准通知
            condition2.signal();

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }
    }

    public void printB() {
        lock.lock();
        try {
            // 1: 判断
            while (status != 2) {
                condition2.await();
            }

            // 2: 业务逻辑
            for (int i = 1; i <= 10; i++) {
                System.out.println(Thread.currentThread().getName() + "  " + i);
            }

            // 3: 通知
            status = 3;
            condition3.signal();

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }
    }

    public void printC() {
        lock.lock();
        try {
            // 1: 判断
            while (status != 3) {
                condition3.await();
            }

            // 2: 业务逻辑
            for (int i = 1; i <= 15; i++) {
                System.out.println(Thread.currentThread().getName() + "  " + i);
            }

            // 3: 通知
            status = 1;
            condition1.signal();

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }
    }
}

public class ThreadOrderAccess {
    public static void main(String[] args) {
        ShareResource shareResource = new ShareResource();

        new Thread(() -> {
            for (int i = 0; i < 10; i++) {
                shareResource.printC();
            }
        }, "C").start();

        new Thread(() -> {
            for (int i = 0; i < 10; i++) {
                shareResource.printA();
            }
        }, "A").start();

        new Thread(() -> {
            for (int i = 0; i < 10; i++) {
                shareResource.printB();
            }
        }, "B").start();


    }
}
